Treatment of Ionized Calcium Level of 1.0 mmol/L

Dosing Algorithm

For an ionized calcium level of 1.0 mmol/L, the American Journal of Kidney Diseases recommends initiating a calcium gluconate infusion at 1-2 mg elemental calcium per kilogram body weight per hour, which translates to approximately 10-20 mL/hour of 10% calcium gluconate solution for a 70 kg adult 1
An ionized calcium of 1.0 mmol/L is below the normal range and requires treatment, particularly if symptomatic or in the context of massive transfusion or post-parathyroidectomy, as stated by the American Journal of Kidney Diseases and Critical Care 1, 2

The American Journal of Kidney Diseases recommends starting calcium gluconate at 1-2 mg elemental calcium/kg/hour 1, 4, 5
For a 70 kg patient, this equals 70-140 mg elemental calcium per hour, according to the American Journal of Kidney Diseases 1
Since 10% calcium gluconate contains 90 mg elemental calcium per 10 mL ampule, this translates to approximately 8-16 mL/hour of 10% calcium gluconate solution, as recommended by the American Journal of Kidney Diseases 1, 6
The American Journal of Kidney Diseases suggests adjusting the infusion rate to maintain ionized calcium in the normal range (1.15-1.36 mmol/L) 1, 4

The American Journal of Kidney Diseases recommends measuring ionized calcium every 4-6 hours during infusion 1, 6
The strength of evidence for this fact is based on the recommendations from the American Journal of Kidney Diseases, which provides a moderate level of evidence 1

The European trauma guidelines specifically recommend calcium chloride for massive transfusion scenarios, as it provides three times more elemental calcium than calcium gluconate 8
Calcium chloride may be preferred in critical situations or with abnormal liver function, according to Critical Care 8

In the post-parathyroidectomy setting, the American Journal of Kidney Diseases recommends this dosing regimen (1-2 mg/kg/hour) when ionized calcium falls below 0.9 mmol/L 1, 6
The American Journal of Kidney Diseases suggests gradually reducing infusion when calcium reaches normal range and remains stable, and transitioning to oral calcium carbonate and calcitriol when oral intake is possible 1, 4, 6
In the massive transfusion setting, Critical Care recommends maintaining ionized calcium above 0.9 mmol/L to preserve coagulation function and cardiovascular stability 2, 3, 9
The 2023 European trauma guidelines emphasize maintaining calcium within normal range during massive transfusion, providing a high level of evidence for this recommendation 8

Accounting for pH effects is crucial, as each 0.1 unit increase in pH decreases ionized calcium by approximately 0.05 mmol/L, according to Critical Care 2, 3, 9